I have no idea where I got this from, but I remember thinking that the little red berries that grew on some trees were highly toxic, so much in fact that I used to hold my breath and run under the trees - in case I accidentally inhaled one. Oh yeah - my mates also told me that it took you 7 years to digest chewing gum - I swallowed it anyway, and still do :-P
A childhood belief about dangerous food

others believed things like this
- I was told that spaghetti grew on trees and i anounced it in class one day in grammer school.— w.b.
- i used to believe that if you swallowed the seeds from apples, trees would grow out of your ears!— Scott Davenport
- I used to think popcorn grew on trees until i was 13.— Davina
- i used to believe that spaggetti grew on trees!Anon
- I used to think that tea grew on trees already in mugs!Anon
- my mother told me if i ever swallowed chewing gum i'd turn into a pig, i believed this for many years.— stuart hayward